def discount(price, isDiscount):
if isDiscount:
price -= 50
return price if price > 0 else 0
while True:
try:
price, month, day, isDiscount = map(float, input().split())
result = price
if month == 11 and day == 11:
print('{:.2f}'.format(discount(result*0.7, isDiscount)))
elif month == 12 and day == 12:
print('{:.2f}'.format(discount(result*0.8, isDiscount)))
else:
print('{:.2f}'.format(result))
except EOFError:
break
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